The present invention relates a body for a valve and a method for manufacturing the same.
Conventionally, a body for a valve provided therein with a valve hole for inserting a valve member therein slidably can be obtained by molding rough material for a body formed with a rough hole to be finished as the valve hole, flow path holes reaching the valve hole from ports opened to an outer face of the body and the like in advance and performing working/grinding on a seat portion coming in contact with a valve member in the rough hole, expansion flow paths for expanding respective flow paths at positions communicating with the valve hole and the like by tools inserted from one end of the rough hole.
However, since such working/grinding must be performed by inserting tools from one end of the rough hole, as described above, there is a problem that there are relatively many constraints other than the shapes of the tools and shapes to be obtained by workings, which results in a difficult work, prolongation of a working time and the like.
A technical problem of the present invention is to simplify and facilitate working/grinding or the like in a valve hole in the above-described body for a valve, particularly working of a recess in the valve hole, thereby reducing a manufacturing cost of the body for a valve.
Another technical problem of the present invention is to increase the number of moldings effected by a single mold in a time of a die cast molding by simplifying the shape of a body for a valve, thereby increasing productivity at this point.
A first body for a valve of the present invention for solving the above problem is a body for a valve provided with a valve hole for inserting a valve member silidably, characterized in that the body is formed by splitting the body on splitting faces including an axial line of the valve hole and mutually joining body portion pieces which are respectively molded individually.
The splitting face of the body for a valve can be a face perpendicular to a direction of a flow path communicating towards the valve hole from a port opened to a body outer face, or it can be a face extending along a direction of a flow path communicating towards the valve hole from a port opened to the body outer face.
A second body for a valve of the present invention is characterized in that the body is formed by splitting the body into a plurality of body portion pieces on splitting faces provided at a position opposed to a body outer face to which a port is opened via the valve hole in parallel with the body outer face and mutually joining the body portion pieces which are respectively molded individually; and the body portion piece having the valve hole has a hole for molding which is opened at a position opposed to a flow path communicating towards the port from the side of the splitting face.
On the other hand, a manufacturing method of the present invention for manufacturing the above-described body for a valve is characterized by comprising the steps of: preliminarily molding respective body portion pieces; after preheating splitting faces of the body portion pieces and wetting them with solder, bringing in close contact with both the splitting faces; and after heating and joining both the splitting faces by friction of the both splitting faces or irradiation of ultrasonic wave, cooling the joined portions to the splitting faces to integrate the body portion pieces.
According to the body for a valve having the above-described constitution and the manufacturing method, since the body is formed by splitting the body in pieces having a shape which facilitates molding of a recess on an inner face of the valve hole or the like, which is performed by die casting, namely, by splitting the body on a splitting face which includes an axial line of the valve hole and which is perpendicular to a direction of a flow path communicating towards the valve hole from the port opened to a body outer face or which extends along a direction of the flow path, or by splitting the body on a splitting face parallel with a face of a body outer face to which a port is opened on a side opposed to the face via the valve hole, and molding split body portion pieces individually, it is unnecessary to insert a tool from one end of a rough hole to perform cutting or the like, as described above, or even if the cutting is performed partially, such a cutting is made very simple and easy. Eventually, a manufacturing cost of the body for a valve can be reduced.
Also, as described above, since a body for a valve is split into a plurality of body portion pieces whose shapes are simplified and molding effected by die casting is facilitated owing to simplification of these shapes, the number of moldings conducted by a single molding die is increased, and productivity is enhanced regarding this point, so that a manufacturing cost of the body for a valve can be reduced. In addition, since, during molding respective body portion pieces, lightening for an unnecessary portion can be performed on splitting faces of the body portion pieces, material can be saved.
Since the split body portion pieces can easily be joined in an air-tight manner by frictional soldering, ultrasonic soldering or the like, as described above, the manufacturing cost can be reduced as compared with the conventional example even when such a step is added.
Incidentally, even when the above-described body for a valve is split and split valve pieces are then joined to one another, working in the valve hole to be performed after joined is not completely removed necessarily. For example, such a working that solder flowed out is removed, a seat portion (a valve seat portion) coming in contact with a seal member is polished and so on must be performed. However, the working is made extremely simple as compared with that in the conventional example.
Here, also, explanation about the case that the body for a valve is split at a face including the axial line of the valve hole or at both sides of the valve hole has been made. However, in order to facilitate molding of the body portion pieces, such a constitution can, of course, be employed that the body are split at an appropriate portion other than the above and molded, as needs, and the split body portion pieces are joined.